How To Calibrate A Speedo?

[jasear]

Well like i explained earlier that my Altezza failed sva because it was showing 30 when it was actually doing 36.

After a lot of research i have been able to find out that if the speedo is even undershowing by a mile its a straight fail on the other hand if it is overshowing by 10% then you could still get away with a pass.

Im sure there must be some way of calibrating the speedo so that i can get the car to pass the sva. Anyone have any idea?

[Bazza]

Well like i explained earlier that my Altezza failed sva because it was showing 30 when it was actually doing 36.

After a lot of research i have been able to find out that if the speedo is even undershowing by a mile its a straight fail on the other hand if it is overshowing by 10% then you could still get away with a pass.

Im sure there must be some way of calibrating the speedo so that i can get the car to pass the sva. Anyone have any idea?

move the numbers :D

[SteveAudioX]

Perhaps a small value resistor ?

[jasear]

can you be a bit more specific as i am a complete ameture.

[ColinBarber]

I would take off the convertor and see if the speedo is still showing under in Km/h. This will tell you if the problem is the speedo or the convertor.

You cannot calibrate the speedos. They are electronic and sealed. The only thing you can do is modify the speed signal going to it (which is what the convertor is doing.)

[Bazza]

slightly off topic

does the speedo have to show mph

i have a recent import (dec03)

with all the certificates and mot

and the speedo still reads in km ??

[jasear]

thanks colin. So youre saying it is possible to manipulate the convertor to perhaps overshow the speed?

Any ideas of how to do that? I mean how exactly would i modify the speed signal going to the convertor?

[ColinBarber]

slightly off topic

does the speedo have to show mph

i have a recent import (dec03)

with all the certificates and mot

and the speedo still reads in km ??

did it go through an SVA?

[jasear]

slightly off topic

does the speedo have to show mph

i have a recent import (dec03)

with all the certificates and mot

and the speedo still reads in km ??

well ure car must be more than 10 years old. As they are the only imported cars that dont require an SVA for some strange reason.

[Bazza]

maybe that explains it

its a 1990 model

[Galee]

Try what colin says first and if you speedo is reading correctly in Km it will be your chip(Convertor). I have had the old 1 or 2 in the past the have failed because of faulty or cheap nasty speedo convertor chips where did you get your from and how much also who fitted it?

Galee

[Martin W]

Bend the needle?

[jasear]

Galee I dont know exactly where the guy got it from. He is going to replace it and try a new one. He has done a lot of sva preparations for all kinds of cars and he has never had any problems with any of the units. I personally think too that its the unit. So fingers crossed the new one shud do the trick.

How ever like martin said, bending the needle might be a good idea. I just want it to pass the sva.